Princess Margaret A Bridesmaid As Two Of Princess Elizabeth ' s Household Wed Princess Margaret was cheif bridesmaid when two members of Princess Elizabeth ' s household were married at St Margarets Westminster , London . the bride Lady Margaret Egerton , is lady in waiting to Princess Elizabeth , and the bridegroom , Mr John R Colville , her Private secretary . Traffic had to be diverted as members of the Royal Family attended , and crowds watched the arrivals . The bride ' s gown , lke her shoes of Edwardian trend , was kept secret until the ceremony , it was designed by Belgian born dress designer Miss Angela Delanghe . Mr and Mrs Churchill leaving the church after the ceremony 20th October 1948